Got a 6637 today.

1) What type of clamps do I need?

2) How long of a piece of 4" pvc is recommended?

 

4" hose clamps and I would go to your local muffler shop and see if they have some scrap 4" stainless exhaust pipe. I got mine free.

 

The OD of the filter neck is going to be over 4". You will need clamps that will open up to ~ 4-1/4" ID. You may find what you need at the hardware store that fits a clothes dryer vent hose. Your NAPA store should able to fix you up with a nice T-bolt clamp, if you so desire.

 

Used the factory clamp plus one 4.5 clamp I bought for $2 and a 4" piece of 4" tubing I had lying around.

 

Is there any reason you couldn't just go with some schedule 40 PVC in 4"?

 

Yes, schedule 40 is pipe and exhaust is tubing. Pipe is measured id and tubing od.

You could stretch it, possibly. Tubing however works as it should.

 

I bought both at Amazon, and they look shiny if that matters to you:

 

OK, you had me thinking on this one as I do know that tubing is OD and pipe is ID but wait...I'm pretty sure that I have measured schedule 40 somewhere, sometime in the past and I was pretty sure that it is an OD measurement for that stuff but not 100% sure. While out in the shop today when I tripped over my 2" schedule 40 it got me thinking and I measured it, it is 2" OD and I'd bet that 4" is OD as well.

 

4" schedule 40 measures - 4 1/2" OD. 2" schedule 40 measures- 2 3/8" OD. Have both in the basement & just checked them.

 

I do stand corrected. That is 1 1/2" and it is shy of 2" OD, sloppy measuring. I'm glad I finally got that figured out.

 

I used a hand rasp plane for woodworking, and simply scruff up and flatten the outside diameter of each filter element I install. U use a rasping motion which creates grooves and deep scratches in the outer face of the filter's neck which are circumferential, and that means they are at right angles to the length of the filter. Then I simply shove the OEM intake hose over the neck and tighten the clamp (I have to remove the hose altogether and work it onto the filter by reaching in from the opposite end of the hose). The hose, under the pressure of the clamps, then bites into the circumferential grooves and scratches on the filter neck for a better grip.

Over time, I have had a few come loose, but it generally works well for me (I'm not typically in a very dusty environment), and my approach is simpler in that I don't have either two clamps or another piece of hard tube to fool with.

Link to a picture of the plane I mentioned... >> https://www.zoro.com/stanley-plane-1...w&gclsrc=aw.ds

 

I clamp AND silicone the exhaust tube to the air filter. You can never be too careful about dusting your engine.

 

If you want to use PVC, go buy a 3" PVC coupler. OD is 4".